1. Field
The invention relates to a polymer composition. More particularly, it relates to a flame retardant rubber modified aromatic vinyl composition.
2. Description of the Related Technology
Generally, acrylonitrile-butadiene-styrene copolymer (hereinafter, ABS resin) has a good balance of physical properties such as processability, mechanical strength, and chemical resistance. Thus, ABS resins are widely used in automobile, electrical appliances, office appliances, electronic goods, toys and so on. However, ABS resins are normally opaque, so, the application of such ABS resin has been restricted.
ABS resin is opaque because the refractive index between the matrix resin and dispersed rubber phase is different. This is usually because light is refracted between the interfaces. Additionally, light with visible wavelength may diffuse depending upon the size of the rubber particles. Therefore, in order to provide an ABS resin with good transparency, the refractive index of the rubber component should be substantially identical to that of the resin component as matrix. One method used is to control the size of the rubber particles to minimize the diffusion of light in the visible ray region.
Depending on the application in which the ABS resin is employed, it may be also advantageous for the resin to also be flame retardant. For example, heat-emitting products, such as computers and facsimiles, may cause a fire unless such resin is flame retardant. One method used to make an ABS transparent resin flame retardant is by the addition of halogenated compounds. However, the inclusion of a halogenated compound for flame retardancy may make the resin toxic. Therefore, non-halogenated compounds for use as flame retardants are desirable.
The use of non-halogenated compounds to impart sufficient flame retardancy to polymers resins is widely known. However, the addition of non-halogenated compounds typically results in the deterioration of heat resistance and transparency for the resin. Thus, there is a need to develop transparent ABS resins that have sufficient flame retardancy and heat resistance.